Man page for ffmpeg

X:\Z_ELEMENTAL_TESTING\ffmpeg_man.txt Wednesday, October 29, 2014 2:11 PM

FFMPEG(1) FFMPEG(1)

NAME

ffmpeg - ffmpeg video converter

SYNOPSIS

ffmpeg [global options] [[infile options][-i infile]]... {[outfile

options] outfile}...

DESCRIPTION

ffmpeg is a very fast video and audio conver ter that can also grab from

a live audio/video source. It can also conve rt between arbitrary sample

rates and resize video on the fly with a hig h quality polyphase filter.

ffmpeg reads from an arbitrary number of inp ut "files" (which can be

regular files, pipes, network streams, grabb ing devices, etc.),

specified by the "-i" option, and writes to an arbitrary number of

output "files", which are specified by a pla in output filename.

Anything found on the command line which can not be interpreted as an

option is considered to be an output filenam e.

Each input or output file can in principle c ontain any number of

streams of different types (video/audio/subt itle/attachment/data).

Allowed number and/or types of streams can b e limited by the container

format. Selecting, which streams from which inputs go into output, is

done either automatically or with the "-map" option (see the Stream

selection chapter).

To refer to input files in options, you must use their indices

(0-based). E.g. the first input file is 0, th e second is 1 etc.

Similarly, streams within a file are referre d to by their indices. E.g.

"2:3" refers to the fourth stream in the thi rd input file. See also the

Stream specifiers chapter.

As a general rule, options are applied to th e next specified file.

Therefore, order is important, and you can h ave the same option on the

command line multiple times. Each occurrence is then applied to the

next input or output file. Exceptions from this rule are the global

options (e.g. verbosity level), which should be specified first.

Do not mix input and output files -- first s pecify all input files,

then all output files. Also do not mix optio ns which belong to

different files. All options apply ONLY to t he next input or output

file and are reset between files.

To set the video bitrate of the output f ile to 64kbit/s:

ffmpeg -i input.avi -b:v 64k output.avi

To force the frame rate of the output fi le to 24 fps:

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ffmpeg -i input.avi -r 24 output.avi

To force the frame rate of the input fil e (valid for raw formats

only) to 1 fps and the frame rate of the output file to 24 fps:

ffmpeg -r 1 -i input.m2v -r 24 output.avi

The format option may be needed for raw inpu t files.

STREAM SELECTION

By default ffmpeg includes only one stream o f each type (video, audio,

subtitle) present in the input files and add s them to each output file.

It picks the "best" of each based upon the f ollowing criteria; for

video it is the stream with the highest reso lution, for audio the

stream with the most channels, for subtitle its the first subtitle

stream. In the case where several streams of the same type rate

equally, the lowest numbered stream is chose n.

You can disable some of those defaults by us ing "-vn/-an/-sn" options.

For full manual control, use the "-map" opti on, which disables the

defaults just described.

OPTIONS

All the numerical options, if not specified otherwise, accept in input

a string representing a number, which may co ntain one of the

International System number postfixes, for e xample K, M, G. If

i is appended after the postfix, powers of 2 are used instead of

powers of 10. The B postfix multiplies the value for 8, and can be

appended after another postfix or used alone . This allows using for

example KB, MiB, G and B as postfix.

Options which do not take arguments are bool ean options, and set the

corresponding value to true. They can be set to false by prefixing with

"no" the option name, for example using "-no foo" in the command line

will set to false the boolean option with na me "foo".

Stream specifiers

Some options are applied per-stream, e.g. bi trate or codec. Stream

specifiers are used to precisely specify whi ch stream(s) does a given

option belong to.

A stream specifier is a string generally app ended to the option name

and separated from it by a colon. E.g. "-cod ec:a:1 ac3" option contains

"a:1" stream specifer, which matches the sec ond audio stream. Therefore

it would select the ac3 codec for the second audio stream.

A stream specifier can match several stream, the option is then applied

to all of them. E.g. the stream specifier in "-b:a 128k" matches all

audio streams.

An empty stream specifier matches all stream s, for example "-codec

copy" or "-codec: copy" would copy all the s treams without reencoding.

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Possible forms of stream specifiers are:

stream_index

Matches the stream with this index. E.g. "-threa ds:1 4" would set

the thread count for the second stream to 4.

stream_type[:stream_index]

stream_type is one of: v for video, a for au dio, s for

subtitle, d for data and t for attachments. If stream_index is

given, then matches stream number stream_index o f this type.

Otherwise matches all streams of this type.

p:program_id[:stream_index]

If stream_index is given, then matches stream nu mber stream_index

in program with id program_id. Otherwise matches all streams in

this program.

Generic options

These options are shared amongst the av* too ls.

-L Show license.

-h, -?, -help, --help

Show help.

-version

Show version.

-formats

Show available formats.

The fields preceding the format names have the f ollowing meanings:

D Decoding available

E Encoding available

-codecs

Show available codecs.

The fields preceding the codec names have the fo llowing meanings:

D Decoding available

E Encoding available

V/A/S

Video/audio/subtitle codec

S Codec supports slices

D Codec supports direct rendering

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T Codec can handle input truncated at random l ocations instead of

only at frame boundaries

-bsfs

Show available bitstream filters.

-protocols

Show available protocols.

-filters

Show available libavfilter filters.

-pix_fmts

Show available pixel formats.

-sample_fmts

Show available sample formats.

-loglevel loglevel | -v loglevel

Set the logging level used by the library. logl evel is a number or

a string containing one of the following values:

quiet

panic

fatal

error

warning

info

verbose

debug

By default the program logs to stderr, if colori ng is supported by

the terminal, colors are used to mark errors and warnings. Log

coloring can be disabled setting the environment variable

AV_LOG_FORCE_NOCOLOR or NO_COLOR, or can be forc ed setting the

environment variable AV_LOG_FORCE_COLOR. The us e of the

environment variable NO_COLOR is deprecated and will be dropped in

a following FFmpeg version.

-report

Dump full command line and console output to a f ile named

"program-YYYYMMDD-HHMMSS.log" in the current dir ectory. This file

can be useful for bug reports. It also implies "-loglevel

verbose".

Note: setting the environment variable "FFREPORT " to any value has

the same effect.

AVOptions

These options are provided directly by the l ibavformat, libavdevice and

libavcodec libraries. To see the list of ava ilable AVOptions, use the

-help option. They are separated into two ca tegories:

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generic

These options can be set for any container, code c or device.

Generic options are listed under AVFormatContext options for

containers/devices and under AVCodecContext opti ons for codecs.

private

These options are specific to the given containe r, device or codec.

Private options are listed under their correspon ding

containers/devices/codecs.

For example to write an ID3v2.3 header inste ad of a default ID3v2.4 to

an MP3 file, use the id3v2_version private o ption of the MP3 muxer:

ffmpeg -i input.flac -id3v2_version 3 out.mp 3

All codec AVOptions are obviously per-stream , so the chapter on stream

specifiers applies to them

Note -nooption syntax cannot be used for boo lean AVOptions, use -option

0/-option 1.

Note2 old undocumented way of specifying per -stream AVOptions by

prepending v/a/s to the options name is now obsolete and will be

removed soon.

Main options

-f fmt (input/output)

Force input or output file format. The format is normally auto

detected for input files and guessed from file e xtension for output

files, so this option is not needed in most case s.

-i filename (input)

input file name

-y (global)

Overwrite output files without asking.

-n (global)

Do not overwrite output files but exit if file e xists.

-c[:stream_specifier] codec (input/output,pe r-stream)

-codec[:stream_specifier] codec (input/outpu t,per-stream)

Select an encoder (when used before an output fi le) or a decoder

(when used before an input file) for one or more streams. codec is

the name of a decoder/encoder or a special value "copy" (output

only) to indicate that the stream is not to be r e-encoded.

For example

ffmpeg -i INPUT -map 0 -c:v libx264 -c:a copy OU TPUT

encodes all video streams with libx264 and copie s all audio

streams.

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For each stream, the last matching "c" option is applied, so

ffmpeg -i INPUT -map 0 -c copy -c:v:1 libx264 -c :a:137 libvorbis OUTPUT

will copy all the streams except the second vide o, which will be

encoded with libx264, and the 138th audio, which will be encoded

with libvorbis.

-t duration (output)

Stop writing the output after its duration reach es duration.

duration may be a number in seconds, or in "hh:m m:ss[.xxx]" form.

-fs limit_size (output)

Set the file size limit.

-ss position (input/output)

When used as an input option (before "-i"), seek s in this input

file to position. When used as an output option (before an output

filename), decodes but discards input until the timestamps reach

position. This is slower, but more accurate.

position may be either in seconds or in "hh:mm:s s[.xxx]" form.

-itsoffset offset (input)

Set the input time offset in seconds. "[-]hh:mm :ss[.xxx]" syntax

is also supported. The offset is added to the t imestamps of the

input files. Specifying a positive offset means that the

corresponding streams are delayed by offset seco nds.

-timestamp time (output)

Set the recording timestamp in the container. T he syntax for time

is:

now|([(YYYY-MM-DD|YYYYMMDD)[T|t| ]]((HH[:MM[:SS[ .m...]]])|(HH[MM[SS[.m...]]]))[Z|z])

If the value is "now" it takes the current time. Time is local

time unless Z or z is appended, in which cas e it is interpreted

as UTC. If the year-month-day part is not speci fied it takes the

current year-month-day.

-metadata[:metadata_specifier] key=value (ou tput,per-metadata)

Set a metadata key/value pair.

An optional metadata_specifier may be given to s et metadata on

streams or chapters. See "-map_metadata" documen tation for details.

This option overrides metadata set with "-map_me tadata". It is also

possible to delete metadata by using an empty va lue.

For example, for setting the title in the output file:

ffmpeg -i in.avi -metadata title="my title" out. flv

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To set the language of the first audio stream:

ffmpeg -i INPUT -metadata:s:a:1 language=eng OUT PUT

-target type (output)

Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50"). type

may be prefixed with "pal-", "ntsc-" or "film-" to use the

corresponding standard. All the format options ( bitrate, codecs,

buffer sizes) are then set automatically. You ca n just type:

ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg

Nevertheless you can specify additional options as long as you know

they do not conflict with the standard, as in:

ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd. mpg

-dframes number (output)

Set the number of data frames to record. This is an alias for

"-frames:d".

-frames[:stream_specifier] framecount (outpu t,per-stream)

Stop writing to the stream after framecount fram es.

-q[:stream_specifier] q (output,per-stream)

-qscale[:stream_specifier] q (output,per-str eam)

Use fixed quality scale (VBR). The meaning of q is codec-dependent.

-filter[:stream_specifier] filter_graph (out put,per-stream)

filter_graph is a description of the filter grap h to apply to the

stream. Use "-filters" to show all the available filters (including

also sources and sinks).

-pre[:stream_specifier] preset_name (output, per-stream)

Specify the preset for matching stream(s).

-stats (global)

Print encoding progress/statistics. On by defaul t.

-attach filename (output)

Add an attachment to the output file. This is su pported by a few

formats like Matroska for e.g. fonts used in ren dering subtitles.

Attachments are implemented as a specific type o f stream, so this

option will add a new stream to the file. It is then possible to

use per-stream options on this stream in the usu al way. Attachment

streams created with this option will be created after all the

other streams (i.e. those created with "-map" or automatic

mappings).

Note that for Matroska you also have to set the mimetype metadata

tag:

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ffmpeg -i INPUT -attach DejaVuSans.ttf -metadata :s:2

mimetype=application/x-truetype-font out.mkv

(assuming that the attachment stream will be thi rd in the output

file).

-dump_attachment[:stream_specifier] filename (input,per-stream)

Extract the matching attachment stream into a fi le named filename.

If filename is empty, then the value of the "fil ename" metadata tag

will be used.

E.g. to extract the first attachment to a file n amed out.ttf:

ffmpeg -dump_attachment:t:0 out.ttf INPUT

To extract all attachments to files determined b y the "filename"

tag:

ffmpeg -dump_attachment:t "" INPUT

Technical note -- attachments are implemented as codec extradata,

so this option can actually be used to extract e xtradata from any

stream, not just attachments.

Video Options

-vframes number (output)

Set the number of video frames to record. This i s an alias for

"-frames:v".

-r[:stream_specifier] fps (input/output,per- stream)

Set frame rate (Hz value, fraction or abbreviati on), (default =

25).

-s[:stream_specifier] size (input/output,per -stream)

Set frame size. The format is wxh (default - sam e as source). The

following abbreviations are recognized:

sqcif

128x96

qcif

176x144

cif 352x288

4cif

704x576

16cif

1408x1152

qqvga

160x120

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qvga

320x240

vga 640x480

svga

800x600

xga 1024x768

uxga

1600x1200

qxga

2048x1536

sxga

1280x1024

qsxga

2560x2048

hsxga

5120x4096

wvga

852x480

wxga

1366x768

wsxga

1600x1024

wuxga

1920x1200

woxga

2560x1600

wqsxga

3200x2048

wquxga

3840x2400

whsxga

6400x4096

whuxga

7680x4800

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cga 320x200

ega 640x350

hd480

852x480

hd720

1280x720

hd1080

1920x1080

-aspect[:stream_specifier] aspect (output,pe r-stream)

Set the video display aspect ratio specified by aspect.

aspect can be a floating point number string, or a string of the

form num:den, where num and den are the numerato r and denominator

of the aspect ratio. For example "4:3", "16:9", "1.3333", and

"1.7777" are valid argument values.

-croptop size

-cropbottom size

-cropleft size

-cropright size

All the crop options have been removed. Use -vf

crop=width:height:x:y instead.

-padtop size

-padbottom size

-padleft size

-padright size

-padcolor hex_color

All the pad options have been removed. Use -vf

pad=width:height:x:y:color instead.

-vn (output)

Disable video recording.

-bt tolerance

Set video bitrate tolerance (in bits, default 40 00k). Has a

minimum value of: (target_bitrate/target_framera te). In 1-pass

mode, bitrate tolerance specifies how far rateco ntrol is willing to

deviate from the target average bitrate value. T his is not related

to min/max bitrate. Lowering tolerance too much has an adverse

effect on quality.

-maxrate bitrate

Set max video bitrate (in bit/s). Requires -buf size to be set.

-minrate bitrate

Set min video bitrate (in bit/s). Most useful i n setting up a CBR

encode:

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ffmpeg -i myfile.avi -b:v 4000k -minrate 4000k - maxrate 4000k -bufsize 1835k out.m2v

It is of little use elsewise.

-bufsize size

Set video buffer verifier buffer size (in bits).

-vcodec codec (output)

Set the video codec. This is an alias for "-code c:v".

-same_quant

Use same quantizer as source (implies VBR).

Note that this is NOT SAME QUALITY. Do not use t his option unless

you know you need it.

-pass n

Select the pass number (1 or 2). It is used to d o two-pass video

encoding. The statistics of the video are record ed in the first

pass into a log file (see also the option -passl ogfile), and in the

second pass that log file is used to generate th e video at the

exact requested bitrate. On pass 1, you may jus t deactivate audio

and set output to null, examples for Windows and Unix:

ffmpeg -i foo.mov -c:v libxvid -pass 1 -an -f ra wvideo -y NUL

ffmpeg -i foo.mov -c:v libxvid -pass 1 -an -f ra wvideo -y /dev/null

-passlogfile prefix (global)

Set two-pass log file name prefix to prefix, the default file name

prefix is ffmpeg2pass. The complete file nam e will be

PREFIX-N.log, where N is a number specific to th e output stream

Note that this option is overwritten by a local option of the same

name when using "-vcodec libx264". That option m aps to the x264

option stats which has a different syntax.

-vlang code

Set the ISO 639 language code (3 letters) of the current video

stream.

-vf filter_graph (output)

filter_graph is a description of the filter grap h to apply to the

input video. Use the option "-filters" to show a ll the available

filters (including also sources and sinks). This is an alias for

"-filter:v".

Advanced Video Options

-pix_fmt[:stream_specifier] format (input/ou tput,per-stream)

Set pixel format. Use "-pix_fmts" to show all th e supported pixel

formats.

-sws_flags flags (input/output)

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Set SwScaler flags.

-g gop_size

Set the group of pictures size.

-intra

deprecated, use -g 1

-vdt n

Discard threshold.

-qmin q

minimum video quantizer scale (VBR)

-qmax q

maximum video quantizer scale (VBR)

-qdiff q

maximum difference between the quantizer scales (VBR)

-qblur blur

video quantizer scale blur (VBR) (range 0.0 - 1. 0)

-qcomp compression

video quantizer scale compression (VBR) (default 0.5). Constant of

ratecontrol equation. Recommended range for defa ult rc_eq: 0.0-1.0

-lmin lambda

minimum video lagrange factor (VBR)

-lmax lambda

max video lagrange factor (VBR)

-mblmin lambda

minimum macroblock quantizer scale (VBR)

-mblmax lambda

maximum macroblock quantizer scale (VBR)

These four options (lmin, lmax, mblmin, mblmax) use lambda units,

but you may use the QP2LAMBDA constant to easily convert from q

units:

ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext

-rc_init_cplx complexity

initial complexity for single pass encoding

-b_qfactor factor

qp factor between P- and B-frames

-i_qfactor factor

qp factor between P- and I-frames

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-b_qoffset offset

qp offset between P- and B-frames

-i_qoffset offset

qp offset between P- and I-frames

-rc_eq equation

Set rate control equation (see section "Expressi on Evaluation")

(default = "tex^qComp").

When computing the rate control equation express ion, besides the

standard functions defined in the section "Expre ssion Evaluation",

the following functions are available:

bits2qp(bits)

qp2bits(qp)

and the following constants are available:

iTex

pTex

tex

mv

fCode

iCount

mcVar

var

isI

isP

isB

avgQP

qComp

avgIITex

avgPITex

avgPPTex

avgBPTex

avgTex

-rc_override[:stream_specifier] override (ou tput,per-stream)

Rate control override for specific intervals, fo rmatted as

"int,int,int" list separated with slashes. Two f irst values are the

beginning and end frame numbers, last one is qua ntizer to use if

positive, or quality factor if negative.

-me_method method

Set motion estimation method to method. Availab le methods are

(from lowest to best quality):

zero

Try just the (0, 0) vector.

phods

log

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x1

hex

umh

epzs

(default method)

full

exhaustive search (slow and marginally bette r than epzs)

-dct_algo algo

Set DCT algorithm to algo. Available values are:

0 FF_DCT_AUTO (default)

1 FF_DCT_FASTINT

2 FF_DCT_INT

3 FF_DCT_MMX

4 FF_DCT_MLIB

5 FF_DCT_ALTIVEC

-idct_algo algo

Set IDCT algorithm to algo. Available values are :

0 FF_IDCT_AUTO (default)

1 FF_IDCT_INT

2 FF_IDCT_SIMPLE

3 FF_IDCT_SIMPLEMMX

4 FF_IDCT_LIBMPEG2MMX

5 FF_IDCT_PS2

6 FF_IDCT_MLIB

7 FF_IDCT_ARM

8 FF_IDCT_ALTIVEC

9 FF_IDCT_SH4

10 FF_IDCT_SIMPLEARM

-er n

Set error resilience to n.

1 FF_ER_CAREFUL (default)

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2 FF_ER_COMPLIANT

3 FF_ER_AGGRESSIVE

4 FF_ER_VERY_AGGRESSIVE

-ec bit_mask

Set error concealment to bit_mask. bit_mask is a bit mask of the

following values:

1 FF_EC_GUESS_MVS (default = enabled)

2 FF_EC_DEBLOCK (default = enabled)

-bf frames

Use frames B-frames (supported for MPEG-1, MPE G-2 and MPEG-4).

-mbd mode

macroblock decision

0 FF_MB_DECISION_SIMPLE: Use mb_cmp (cannot ch ange it yet in

ffmpeg).

1 FF_MB_DECISION_BITS: Choose the one which ne eds the fewest

bits.

2 FF_MB_DECISION_RD: rate distortion

-4mv

Use four motion vector by macroblock (MPEG-4 onl y).

-part

Use data partitioning (MPEG-4 only).

-bug param

Work around encoder bugs that are not auto-detec ted.

-strict strictness

How strictly to follow the standards.

-aic

Enable Advanced intra coding (h263+).

-umv

Enable Unlimited Motion Vector (h263+)

-deinterlace

Deinterlace pictures.

-ilme

Force interlacing support in encoder (MPEG-2 and MPEG-4 only). Use

this option if your input file is interlaced and you want to keep

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the interlaced format for minimum losses. The a lternative is to

deinterlace the input stream with -deinterlace, but deinterlacing

introduces losses.

-psnr

Calculate PSNR of compressed frames.

-vstats

Dump video coding statistics to vstats_HHMMSS.lo g.

-vstats_file file

Dump video coding statistics to file.

-top[:stream_specifier] n (output,per-stream )

top=1/bottom=0/auto=-1 field first

-dc precision

Intra_dc_precision.

-vtag fourcc/tag (output)

Force video tag/fourcc. This is an alias for "-t ag:v".

-qphist (global)

Show QP histogram

-vbsf bitstream_filter

Deprecated see -bsf

-force_key_frames[:stream_specifier] time[,t ime...] (output,per-stream)

Force key frames at the specified timestamps, mo re precisely at the

first frames after each specified time. This op tion can be useful

to ensure that a seek point is present at a chap ter mark or any

other designated place in the output file. The timestamps must be

specified in ascending order.

-copyinkf[:stream_specifier] (output,per-str eam)

When doing stream copy, copy also non-key frames found at the

beginning.

Audio Options

-aframes number (output)

Set the number of audio frames to record. This i s an alias for

"-frames:a".

-ar[:stream_specifier] freq (input/output,pe r-stream)

Set the audio sampling frequency. For output str eams it is set by

default to the frequency of the corresponding in put stream. For

input streams this option only makes sense for a udio grabbing

devices and raw demuxers and is mapped to the co rresponding demuxer

options.

-aq q (output)

Set the audio quality (codec-specific, VBR). Thi s is an alias for

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-q:a.

-ac[:stream_specifier] channels (input/outpu t,per-stream)

Set the number of audio channels. For output str eams it is set by

default to the number of input audio channels. F or input streams

this option only makes sense for audio grabbing devices and raw

demuxers and is mapped to the corresponding demu xer options.

-an (output)

Disable audio recording.

-acodec codec (input/output)

Set the audio codec. This is an alias for "-code c:a".

-sample_fmt[:stream_specifier] sample_fmt (o utput,per-stream)

Set the audio sample format. Use "-sample_fmts" to get a list of

supported sample formats.

Advanced Audio options:

-atag fourcc/tag (output)

Force audio tag/fourcc. This is an alias for "-t ag:a".

-audio_service_type type

Set the type of service that the audio stream co ntains.

ma Main Audio Service (default)

ef Effects

vi Visually Impaired

hi Hearing Impaired

di Dialogue

co Commentary

em Emergency

vo Voice Over

ka Karaoke

-absf bitstream_filter

Deprecated, see -bsf

Subtitle options:

-slang code

Set the ISO 639 language code (3 letters) of the current subtitle

stream.

-scodec codec (input/output)

Set the subtitle codec. This is an alias for "-c odec:s".

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-sn (output)

Disable subtitle recording.

-sbsf bitstream_filter

Deprecated, see -bsf

Audio/Video grab options

-isync (global)

Synchronize read on input.

Advanced options

-map

[-]input_file_id[:stream_specifier][,sync_fi le_id[:stream_specifier]]

(output)

Designate one or more input streams as a source for the output

file. Each input stream is identified by the inp ut file index

input_file_id and the input stream index input_s tream_id within the

input file. Both indices start at 0. If specifie d,

sync_file_id:stream_specifier sets which input s tream is used as a

presentation sync reference.

The first "-map" option on the command line spec ifies the source

for output stream 0, the second "-map" option sp ecifies the source

for output stream 1, etc.

A "-" character before the stream identifier cre ates a "negative"

mapping. It disables matching streams from alre ady created

mappings.

For example, to map ALL streams from the first i nput file to output

ffmpeg -i INPUT -map 0 output

For example, if you have two audio streams in th e first input file,

these streams are identified by "0:0" and "0:1". You can use "-map"

to select which streams to place in an output fi le. For example:

ffmpeg -i INPUT -map 0:1 out.wav

will map the input stream in INPUT identified by "0:1" to the

(single) output stream in out.wav.

For example, to select the stream with index 2 f rom input file

a.mov (specified by the identifier "0:2"), and s tream with index 6

from input b.mov (specified by the identifier "1 :6"), and copy them

to the output file out.mov:

ffmpeg -i a.mov -i b.mov -c copy -map 0:2 -map 1 :6 out.mov

To select all video and the third audio stream f rom an input file:

ffmpeg -i INPUT -map 0:v -map 0:a:2 OUTPUT

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To map all the streams except the second audio, use negative

mappings

ffmpeg -i INPUT -map 0 -map -0:a:1 OUTPUT

Note that using this option disables the default mappings for this

output file.

-map_channel

[input_file_id.stream_specifier.channel_id|- 1][:output_file_id.stream_specifier]

Map an audio channel from a given input to an ou tput. If

output_file_id.stream_specifier are not set, the audio channel will

be mapped on all the audio streams.

Using "-1" instead of input_file_id.stream_speci fier.channel_id

will map a muted channel.

For example, assuming INPUT is a stereo audio fi le, you can switch

the two audio channels with the following comman d:

ffmpeg -i INPUT -map_channel 0.0.1 -map_channel 0.0.0 OUTPUT

If you want to mute the first channel and keep t he second:

ffmpeg -i INPUT -map_channel -1 -map_channel 0.0 .1 OUTPUT

The order of the "-map_channel" option specifies the order of the

channels in the output stream. The output channe l layout is guessed

from the number of channels mapped (mono if one "-map_channel",

stereo if two, etc.). Using "-ac" in combination of "-map_channel"

makes the channel gain levels to be updated if c hannel layouts

dont match (for instance two "-map_channel" opt ions and "-ac 6").

You can also extract each channel of an INPUT to specific outputs;

the following command extract each channel of th e audio stream

(file 0, stream 0) to the respective OUTPUT_CH0 and OUTPUT_CH1:

ffmpeg -i INPUT -map_channel 0.0.0 OUTPUT_CH0 -m ap_channel 0.0.1 OUTPUT_CH1

The following example split the channels of a st ereo input into

streams:

ffmpeg -i stereo.wav -map 0:0 -map 0:0 -map_chan nel 0.0.0:0.0 -map_channel 0.0.1:0.1

-y out.ogg

Note that currently each output stream can only contain channels

from a single input stream; you cant for exampl e use

"-map_channel" to pick multiple input audio chan nels contained in

different streams (from the same or different fi les) and merge them

into a single output stream. It is therefore not currently

possible, for example, to turn two separate mono streams into a

single stereo stream. However spliting a stereo stream into two

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single channel mono streams is possible.

-map_metadata[:metadata_spec_out] infile[:me tadata_spec_in]

(output,per-metadata)

Set metadata information of the next output file from infile. Note

that those are file indices (zero-based), not fi lenames. Optional

metadata_spec_in/out parameters specify, which m etadata to copy. A

metadata specifier can have the following forms:

g global metadata, i.e. metadata that applies to the whole file

s[:stream_spec]

per-stream metadata. stream_spec is a stream specifier as

described in the Stream specifiers chapter. In an input

metadata specifier, the first matching strea m is copied from.

In an output metadata specifier, all matchin g streams are

copied to.

c:chapter_index

per-chapter metadata. chapter_index is the z ero-based chapter

index.

p:program_index

per-program metadata. program_index is the z ero-based program

index.

If metadata specifier is omitted, it defaults to global.

By default, global metadata is copied from the f irst input file,

per-stream and per-chapter metadata is copied al ong with

streams/chapters. These default mappings are dis abled by creating

any mapping of the relevant type. A negative fil e index can be used

to create a dummy mapping that just disables aut omatic copying.

For example to copy metadata from the first stre am of the input

file to global metadata of the output file:

ffmpeg -i in.ogg -map_metadata 0:s:0 out.mp3

To do the reverse, i.e. copy global metadata to all audio streams:

ffmpeg -i in.mkv -map_metadata:s:a 0:g out.mkv

Note that simple 0 would work as well in this ex ample, since global

metadata is assumed by default.

-map_chapters input_file_index (output)

Copy chapters from input file with index input_f ile_index to the

next output file. If no chapter mapping is speci fied, then chapters

are copied from the first input file with at lea st one chapter. Use

a negative file index to disable any chapter cop ying.

-debug category

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Print specific debug info. category is a number or a string

containing one of the following values:

bitstream

buffers

picture buffer allocations

bugs

dct_coeff

er error recognition

mb_type

macroblock (MB) type

mmco

memory management control operations (H.264)

mv motion vector

pict

picture info

pts

qp per-block quantization parameter (QP)

rc rate control

skip

startcode

thread_ops

threading operations

vis_mb_type

visualize block types

vis_qp

visualize quantization parameter (QP), lower QP are tinted

greener

-benchmark (global)

Show benchmarking information at the end of an e ncode. Shows CPU

time used and maximum memory consumption. Maxim um memory

consumption is not supported on all systems, it will usually

display as 0 if not supported.

-timelimit duration (global)

Exit after ffmpeg has been running for duration seconds.

-dump (global)

Dump each input packet to stderr.

-hex (global)

When dumping packets, also dump the payload.

-21-


-ps size

Set RTP payload size in bytes.

-re (input)

Read input at native frame rate. Mainly used to simulate a grab

device.

-loop_input

Loop over the input stream. Currently it works o nly for image

streams. This option is used for automatic FFser ver testing. This

option is deprecated, use -loop 1.

-loop_output number_of_times

Repeatedly loop output for formats that support looping such as

animated GIF (0 will loop the output infinitely) . This option is

deprecated, use -loop.

-threads count

Thread count.

-vsync parameter

Video sync method.

0, passthrough

Each frame is passed with its timestamp from the demuxer to the

muxer.

1, cfr

Frames will be duplicated and dropped to ach ieve exactly the

requested constant framerate.

2, vfr

Frames are passed through with their timesta mp or dropped so as

to prevent 2 frames from having the same tim estamp.

-1, auto

Chooses between 1 and 2 depending on muxer c apabilities. This

is the default method.

With -map you can select from which stream the t imestamps should be

taken. You can leave either video or audio uncha nged and sync the

remaining stream(s) to the unchanged one.

-async samples_per_second

Audio sync method. "Stretches/squeezes" the audi o stream to match

the timestamps, the parameter is the maximum sam ples per second by

which the audio is changed. -async 1 is a special case where only

the start of the audio stream is corrected witho ut any later

correction.

-copyts

Copy timestamps from input to output.

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-copytb

Copy input stream time base from input to output when stream

copying.

-shortest

Finish encoding when the shortest input stream e nds.

-dts_delta_threshold

Timestamp discontinuity delta threshold.

-muxdelay seconds (input)

Set the maximum demux-decode delay.

-muxpreload seconds (input)

Set the initial demux-decode delay.

-streamid output-stream-index:new-value (out put)

Assign a new stream-id value to an output stream . This option

should be specified prior to the output filename to which it

applies. For the situation where multiple outpu t files exist, a

streamid may be reassigned to a different value.

For example, to set the stream 0 PID to 33 and t he stream 1 PID to

36 for an output mpegts file:

ffmpeg -i infile -streamid 0:33 -streamid 1:36 o ut.ts

-bsf[:stream_specifier] bitstream_filters (o utput,per-stream)

Set bitstream filters for matching streams. bist ream_filters is a

comma-separated list of bitstream filters. Use t he "-bsfs" option

to get the list of bitstream filters.

ffmpeg -i h264.mp4 -c:v copy -vbsf h264_mp4toann exb -an out.h264

ffmpeg -i file.mov -an -vn -sbsf mov2textsub -c: s copy -f rawvideo sub.txt

-tag[:stream_specifier] codec_tag (per-strea m)

Force a tag/fourcc for matching streams.

-timecode hh:mm:ssSEPff

Specify Timecode for writing. SEP is : for non drop timecode and

; (or .) for drop.

ffmpeg -i input.mpg -timecode 01:02:03.04 -r 300 00/1001 -s ntsc output.mpg

Preset files

A preset file contains a sequence of option= value pairs, one for each

line, specifying a sequence of options which would be awkward to

specify on the command line. Lines starting with the hash (#)

character are ignored and are used to provid e comments. Check the

presets directory in the FFmpeg source tree for examples.

-23-


Preset files are specified with the "vpre", "apre", "spre", and "fpre"

options. The "fpre" option takes the filenam e of the preset instead of

a preset name as input and can be used for a ny kind of codec. For the

"vpre", "apre", and "spre" options, the opti ons specified in a preset

file are applied to the currently selected c odec of the same type as

the preset option.

The argument passed to the "vpre", "apre", a nd "spre" preset options

identifies the preset file to use according to the following rules:

First ffmpeg searches for a file named arg.f fpreset in the directories

$FFMPEG_DATADIR (if set), and $HOME/.ffmpeg, and in the datadir defined

at configuration time (usually PREFIX/share/ ffmpeg) or in a ffpresets

folder along the executable on win32, in tha t order. For example, if

the argument is "libx264-max", it will searc h for the file

libx264-max.ffpreset.

If no such file is found, then ffmpeg will s earch for a file named

codec_name-arg.ffpreset in the above-mention ed directories, where

codec_name is the name of the codec to which the preset file options

will be applied. For example, if you select the video codec with

"-vcodec libx264" and use "-vpre max", then it will search for the file

libx264-max.ffpreset.

TIPS

For streaming at very low bitrate applic ation, use a low frame rate

and a small GOP size. This is especially true fo r RealVideo where

the Linux player does not seem to be very fast, so it can miss

frames. An example is:

ffmpeg -g 3 -r 3 -t 10 -b:v 50k -s qcif -f rv10 /tmp/b.rm

The parameter q which is displayed whi le encoding is the current

quantizer. The value 1 indicates that a very goo d quality could be

achieved. The value 31 indicates the worst quali ty. If q=31 appears

too often, it means that the encoder cannot comp ress enough to meet

your bitrate. You must either increase the bitra te, decrease the

frame rate or decrease the frame size.

If your computer is not fast enough, you can speed up the

compression at the expense of the compression ra tio. You can use

-me zero to speed up motion estimation, and - intra to disable

motion estimation completely (you have only I-fr ames, which means

it is about as good as JPEG compression).

To have very low audio bitrates, reduce the sampling frequency

(down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3).

To have a constant quality (but a variab le bitrate), use the option

-qscale n when n is between 1 (excellent qua lity) and 31 (worst

quality).

-24-


EXAMPLES

Preset files

A preset file contains a sequence of option= value pairs, one for each

line, specifying a sequence of options which can be specified also on

the command line. Lines starting with the ha sh (#) character are

ignored and are used to provide comments. Em pty lines are also ignored.

Check the presets directory in the FFmpeg so urce tree for examples.

Preset files are specified with the "pre" op tion, this option takes a

preset name as input. FFmpeg searches for a file named

preset_name.avpreset in the directories $AVC ONV_DATADIR (if set), and

$HOME/.ffmpeg, and in the data directory def ined at configuration time

(usually $PREFIX/share/ffmpeg) in that order . For example, if the

argument is "libx264-max", it will search fo r the file

libx264-max.avpreset.

Video and Audio grabbing

If you specify the input format and device t hen ffmpeg can grab video

and audio directly.

ffmpeg -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg

Or with an ALSA audio source (mono input, ca rd id 1) instead of OSS:

ffmpeg -f alsa -ac 1 -i hw:1 -f video4linux2 -i /dev/video0 /tmp/out.mpg

Note that you must activate the right video source and channel before

launching ffmpeg with any TV viewer such as

xawtv ("http://linux.bytesex.org/xawtv/") by Gerd K norr. You also have

to set the audio recording levels correctly with a standard mixer.

X11 grabbing

Grab the X11 display with ffmpeg via

ffmpeg -f x11grab -s cif -r 25 -i :0.0 /tmp/ out.mpg

0.0 is display.screen number of your X11 ser ver, same as the DISPLAY

environment variable.

ffmpeg -f x11grab -s cif -r 25 -i :0.0+10,20 /tmp/out.mpg

0.0 is display.screen number of your X11 ser ver, same as the DISPLAY

environment variable. 10 is the x-offset and 20 the y-offset for the

grabbing.

Video and Audio file format conversion

Any supported file format and protocol can s erve as input to ffmpeg:

Examples:

You can use YUV files as input:

ffmpeg -i /tmp/test%d.Y /tmp/out.mpg

-25-


It will use the files:

/tmp/test0.Y, /tmp/test0.U, /tmp/test0.V,

/tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc...

The Y files use twice the resolution of the U an d V files. They are

raw files, without header. They can be generated by all decent

video decoders. You must specify the size of the image with the -s

option if ffmpeg cannot guess it.

You can input from a raw YUV420P file:

ffmpeg -i /tmp/test.yuv /tmp/out.avi

test.yuv is a file containing raw YUV planar dat a. Each frame is

composed of the Y plane followed by the U and V planes at half

vertical and horizontal resolution.

You can output to a raw YUV420P file:

ffmpeg -i mydivx.avi hugefile.yuv

You can set several input files and outp ut files:

ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /t mp/a.mpg

Converts the audio file a.wav and the raw YUV vi deo file a.yuv to

MPEG file a.mpg.

You can also do audio and video conversi ons at the same time:

ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2

Converts a.wav to MPEG audio at 22050 Hz sample rate.

You can encode to several formats at the same time and define a

mapping from input stream to output streams:

ffmpeg -i /tmp/a.wav -map 0:a -b:a 64k /tmp/a.mp 2 -map 0:a -b:a 128k /tmp/b.mp2

Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits.

-map file:index specifies which input stream i s used for each

output stream, in the order of the definition of output streams.

You can transcode decrypted VOBs:

ffmpeg -i snatch_1.vob -f avi -c:v mpeg4 -b:v 80 0k -g 300 -bf 2 -c:a libmp3lame -b:a

128k snatch.avi

This is a typical DVD ripping example; the input is a VOB file, the

output an AVI file with MPEG-4 video and MP3 aud io. Note that in

this command we use B-frames so the MPEG-4 strea m is DivX5

-26-


compatible, and GOP size is 300 which means one intra frame every

10 seconds for 29.97fps input video. Furthermore , the audio stream

is MP3-encoded so you need to enable LAME suppor t by passing

"--enable-libmp3lame" to configure. The mapping i s particularly

useful for DVD transcoding to get the desired au dio language.

NOTE: To see the supported input formats, use "f fmpeg -formats".

You can extract images from a video, or create a video from many

images:

For extracting images from a video:

ffmpeg -i foo.avi -r 1 -s WxH -f image2 foo-%03d .jpeg

This will extract one video frame per second fro m the video and

will output them in files named foo-001.jpeg, fo o-002.jpeg, etc.

Images will be rescaled to fit the new WxH value s.

If you want to extract just a limited number of frames, you can use

the above command in combination with the -vfram es or -t option, or

in combination with -ss to start extracting from a certain point in

time.

For creating a video from many images:

ffmpeg -f image2 -i foo-%03d.jpeg -r 12 -s WxH f oo.avi

The syntax "foo-%03d.jpeg" specifies to use a de cimal number

composed of three digits padded with zeroes to e xpress the sequence

number. It is the same syntax supported by the C printf function,

but only formats accepting a normal integer are suitable.

You can put many streams of the same typ e in the output:

ffmpeg -i test1.avi -i test2.avi -map 0.3 -map 0 .2 -map 0.1 -map 0.0 -c copy

test12.nut

The resulting output file test12.avi will contai n first four

streams from the input file in reverse order.

EXPRESSION EVALUATION

When evaluating an arithmetic expression, FF mpeg uses an internal

formula evaluator, implemented through the l ibavutil/eval.h interface.

An expression may contain unary, binary oper ators, constants, and

functions.

Two expressions expr1 and expr2 can be combi ned to form another

expression "expr1;expr2". expr1 and expr2 a re evaluated in turn, and

the new expression evaluates to the value of expr2.

The following binary operators are available : "+", "-", "*", "/", "^".

-27-


The following unary operators are available: "+", "-".

The following functions are available:

sinh(x)

cosh(x)

tanh(x)

sin(x)

cos(x)

tan(x)

atan(x)

asin(x)

acos(x)

exp(x)

log(x)

abs(x)

squish(x)

gauss(x)

isnan(x)

Return 1.0 if x is NAN, 0.0 otherwise.

mod(x, y)

max(x, y)

min(x, y)

eq(x, y)

gte(x, y)

gt(x, y)

lte(x, y)

lt(x, y)

st(var, expr)

Allow to store the value of the expression expr in an internal

variable. var specifies the number of the variab le where to store

the value, and it is a value ranging from 0 to 9 . The function

returns the value stored in the internal variabl e. Note, Variables

are currently not shared between expressions.

ld(var)

Allow to load the value of the internal variable with number var,

which was previously stored with st(var, expr). The function

returns the loaded value.

while(cond, expr)

Evaluate expression expr while the expression co nd is non-zero, and

returns the value of the last expr evaluation, o r NAN if cond was

always false.

ceil(expr)

Round the value of expression expr upwards to th e nearest integer.

For example, "ceil(1.5)" is "2.0".

floor(expr)

Round the value of expression expr downwards to the nearest

-28-


integer. For example, "floor(-1.5)" is "-2.0".

trunc(expr)

Round the value of expression expr towards zero to the nearest

integer. For example, "trunc(-1.5)" is "-1.0".

sqrt(expr)

Compute the square root of expr. This is equival ent to "(expr)^.5".

not(expr)

Return 1.0 if expr is zero, 0.0 otherwise.

pow(x, y)

Compute the power of x elevated y, it is equival ent to "(x)^(y)".

random(x)

Return a pseudo random value between 0.0 and 1.0 . x is the index of

the internal variable which will be used to save the seed/state.

hypot(x, y)

This function is similar to the C function with the same name; it

returns "sqrt(x*x + y*y)", the length of the hyp otenuse of a right

triangle with sides of length x and y, or the di stance of the point

(x, y) from the origin.

gcd(x, y)

Return the greatest common divisor of x and y. I f both x and y are

0 or either or both are less than zero then beha vior is undefined.

if(x, y)

Evaluate x, and if the result is non-zero return the result of the

evaluation of y, return 0 otherwise.

ifnot(x, y)

Evaluate x, and if the result is zero return the result of the

evaluation of y, return 0 otherwise.

The following constants are available:

PI area of the unit disc, approximately 3.1 4

E exp(1) (Eulers number), approximately 2 .718

PHI golden ratio (1+sqrt(5))/2, approximatel y 1.618

Assuming that an expression is considered "t rue" if it has a non-zero

value, note that:

"*" works like AND

"+" works like OR

and the construct:

-29-


if A then B else C

is equivalent to

if(A,B) + ifnot(A,C)

In your C code, you can extend the list of u nary and binary functions,

and define recognized constants, so that the y are available for your

expressions.

The evaluator also recognizes the Internatio nal System number

postfixes. If i is appended after the post fix, powers of 2 are used

instead of powers of 10. The B postfix mul tiplies the value for 8,

and can be appended after another postfix or used alone. This allows

using for example KB, MiB, G and B a s postfix.

Follows the list of available International System postfixes, with

indication of the corresponding powers of 10 and of 2.

y -24 / -80

z -21 / -70

a -18 / -60

f -15 / -50

p -12 / -40

n -9 / -30

u -6 / -20

m -3 / -10

c -2

d -1

h 2

k 3 / 10

K 3 / 10

M 6 / 20

G 9 / 30

T 12 / 40

P 15 / 40

-30-


E 18 / 50

Z 21 / 60

Y 24 / 70

DECODERS

Decoders are configured elements in FFmpeg w hich allow the decoding of

multimedia streams.

When you configure your FFmpeg build, all th e supported native decoders

are enabled by default. Decoders requiring a n external library must be

enabled manually via the corresponding "--en able-lib" option. You can

list all available decoders using the config ure option

"--list-decoders".

You can disable all the decoders with the co nfigure option

"--disable-decoders" and selectively enable / disable single decoders

with the options "--enable-decoder=DECODER" /

"--disable-decoder=DECODER".

The option "-codecs" of the ff* tools will d isplay the list of enabled

decoders.

VIDEO DECODERS

A description of some of the currently avail able video decoders

follows.

rawvideo

Raw video decoder.

This decoder decodes rawvideo streams.

Options

top top_field_first

Specify the assumed field type of the input vide o.

-1 the video is assumed to be progressive (defa ult)

0 bottom-field-first is assumed

1 top-field-first is assumed

AUDIO DECODERS

ffwavesynth

Internal wave synthetizer.

This decoder generates wave patterns accordi ng to predefined sequences.

Its use is purely internal and the format of the data it accepts is not

publicly documented.

-31-


ENCODERS

Encoders are configured elements in FFmpeg w hich allow the encoding of

multimedia streams.

When you configure your FFmpeg build, all th e supported native encoders

are enabled by default. Encoders requiring a n external library must be

enabled manually via the corresponding "--en able-lib" option. You can

list all available encoders using the config ure option

"--list-encoders".

You can disable all the encoders with the co nfigure option

"--disable-encoders" and selectively enable / disable single encoders

with the options "--enable-encoder=ENCODER" /

"--disable-encoder=ENCODER".

The option "-codecs" of the ff* tools will d isplay the list of enabled

encoders.

AUDIO ENCODERS

A description of some of the currently avail able audio encoders

follows.

ac3 and ac3_fixed

AC-3 audio encoders.

These encoders implement part of ATSC A/52:2 010 and ETSI TS 102 366, as

well as the undocumented RealAudio 3 (a.k.a. dnet).

The ac3 encoder uses floating-point math, wh ile the ac3_fixed encoder

only uses fixed-point integer math. This doe s not mean that one is

always faster, just that one or the other ma y be better suited to a

particular system. The floating-point encode r will generally produce

better quality audio for a given bitrate. Th e ac3_fixed encoder is not

the default codec for any of the output form ats, so it must be

specified explicitly using the option "-acod ec ac3_fixed" in order to

use it.

AC-3 Metadata

The AC-3 metadata options are used to set pa rameters that describe the

audio, but in most cases do not affect the a udio encoding itself. Some

of the options do directly affect or influen ce the decoding and

playback of the resulting bitstream, while o thers are just for

informational purposes. A few of the options will add bits to the

output stream that could otherwise be used f or audio data, and will

thus affect the quality of the output. Those will be indicated

accordingly with a note in the option list b elow.

These parameters are described in detail in several publicly-available

documents.

*

-32-


*

*

*

Metadata Control Options

-per_frame_metadata boolean

Allow Per-Frame Metadata. Specifies if the encod er should check for

changing metadata for each frame.

0 The metadata values set at initialization wi ll be used for

every frame in the stream. (default)

1 Metadata values can be changed before encodi ng each frame.

Downmix Levels

-center_mixlev level

Center Mix Level. The amount of gain the decoder should apply to

the center channel when downmixing to stereo. Th is field will only

be written to the bitstream if a center channel is present. The

value is specified as a scale factor. There are 3 valid values:

0.707

Apply -3dB gain

0.595

Apply -4.5dB gain (default)

0.500

Apply -6dB gain

-surround_mixlev level

Surround Mix Level. The amount of gain the decod er should apply to

the surround channel(s) when downmixing to stere o. This field will

only be written to the bitstream if one or more surround channels

are present. The value is specified as a scale f actor. There are 3

valid values:

0.707

Apply -3dB gain

0.500

Apply -6dB gain (default)

0.000

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Silence Surround Channel(s)

Audio Production Information

Audio Production Information is optional inf ormation describing the

mixing environment. Either none or both of the fields are written to

the bitstream.

-mixing_level number

Mixing Level. Specifies peak sound pressure leve l (SPL) in the

production environment when the mix was mastered . Valid values are

80 to 111, or -1 for unknown or not indicated. T he default value is

-1, but that value cannot be used if the Audio P roduction

Information is written to the bitstream. Therefo re, if the

"room_type" option is not the default value, the "mixing_level"

option must not be -1.

-room_type type

Room Type. Describes the equalization used durin g the final mixing

session at the studio or on the dubbing stage. A large room is a

dubbing stage with the industry standard X-curve equalization; a

small room has flat equalization. This field wi ll not be written

to the bitstream if both the "mixing_level" opti on and the

"room_type" option have the default values.

0

notindicated

Not Indicated (default)

1

large

Large Room

2

small

Small Room

Other Metadata Options

-copyright boolean

Copyright Indicator. Specifies whether a copyrig ht exists for this

audio.

0

off No Copyright Exists (default)

1

on Copyright Exists

-dialnorm value

Dialogue Normalization. Indicates how far the av erage dialogue

level of the program is below digital 100% full scale (0 dBFS).

This parameter determines a level shift during a udio reproduction

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that sets the average volume of the dialogue to a preset level. The

goal is to match volume level between program so urces. A value of

-31dB will result in no volume level change, rel ative to the source

volume, during audio reproduction. Valid values are whole numbers

in the range -31 to -1, with -31 being the defau lt.

-dsur_mode mode

Dolby Surround Mode. Specifies whether the stere o signal uses Dolby

Surround (Pro Logic). This field will only be wr itten to the

bitstream if the audio stream is stereo. Using t his option does NOT

mean the encoder will actually apply Dolby Surro und processing.

0

notindicated


1

off Not Dolby Surround Encoded

2

on Dolby Surround Encoded

-original boolean

Original Bit Stream Indicator. Specifies whether this audio is from

the original source and not a copy.

0

off Not Original Source

1

on Original Source (default)

Extended Bitstream Information

The extended bitstream options are part of t he Alternate Bit Stream

Syntax as specified in Annex D of the A/52:2 010 standard. It is grouped

into 2 parts. If any one parameter in a gro up is specified, all values

in that group will be written to the bitstre am. Default values are

used for those that are written but have not been specified. If the

mixing levels are written, the decoder will use these values instead of

the ones specified in the "center_mixlev" an d "surround_mixlev" options

if it supports the Alternate Bit Stream Synt ax.

Extended Bitstream Information - Part 1

-dmix_mode mode

Preferred Stereo Downmix Mode. Allows the user t o select either

Lt/Rt (Dolby Surround) or Lo/Ro (normal stereo) as the preferred

stereo downmix mode.

0

notindicated


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1

ltrt

Lt/Rt Downmix Preferred

2

loro

Lo/Ro Downmix Preferred

-ltrt_cmixlev level

Lt/Rt Center Mix Level. The amount of gain the d ecoder should apply

to the center channel when downmixing to stereo in Lt/Rt mode.

1.414

Apply +3dB gain

1.189

Apply +1.5dB gain

1.000

Apply 0dB gain

0.841

Apply -1.5dB gain

0.707

Apply -3.0dB gain

0.595


0.500

Apply -6.0dB gain

0.000

Silence Center Channel

-ltrt_surmixlev level

Lt/Rt Surround Mix Level. The amount of gain the decoder should

apply to the surround channel(s) when downmixing to stereo in Lt/Rt

mode.

0.841

Apply -1.5dB gain

0.707

Apply -3.0dB gain

0.595

Apply -4.5dB gain

0.500


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0.000


-loro_cmixlev level

Lo/Ro Center Mix Level. The amount of gain the d ecoder should apply

to the center channel when downmixing to stereo in Lo/Ro mode.

1.414

Apply +3dB gain

1.189

Apply +1.5dB gain

1.000

Apply 0dB gain

0.841

Apply -1.5dB gain

0.707

Apply -3.0dB gain

0.595


0.500

Apply -6.0dB gain

0.000

Silence Center Channel

-loro_surmixlev level

Lo/Ro Surround Mix Level. The amount of gain the decoder should

apply to the surround channel(s) when downmixing to stereo in Lo/Ro

mode.

0.841

Apply -1.5dB gain

0.707

Apply -3.0dB gain

0.595

Apply -4.5dB gain

0.500


0.000


Extended Bitstream Information - Part 2

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-dsurex_mode mode

Dolby Surround EX Mode. Indicates whether the st ream uses Dolby

Surround EX (7.1 matrixed to 5.1). Using this op tion does NOT mean

the encoder will actually apply Dolby Surround E X processing.

0

notindicated


1

on Dolby Surround EX Off

2

off Dolby Surround EX On

-dheadphone_mode mode

Dolby Headphone Mode. Indicates whether the stre am uses Dolby

Headphone encoding (multi-channel matrixed to 2. 0 for use with

headphones). Using this option does NOT mean the encoder will

actually apply Dolby Headphone processing.

0

notindicated


1

on Dolby Headphone Off

2

off Dolby Headphone On

-ad_conv_type type

A/D Converter Type. Indicates whether the audio has passed through

HDCD A/D conversion.

0

standard

Standard A/D Converter (default)

1

hdcd

HDCD A/D Converter

Other AC-3 Encoding Options

-stereo_rematrixing boolean

Stereo Rematrixing. Enables/Disables use of rema trixing for stereo

input. This is an optional AC-3 feature that inc reases quality by

selectively encoding the left/right channels as mid/side. This

option is enabled by default, and it is highly r ecommended that it

be left as enabled except for testing purposes.

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Floating-Point-Only AC-3 Encoding Options

These options are only valid for the floatin g-point encoder and do not

exist for the fixed-point encoder due to the corresponding features not

being implemented in fixed-point.

-channel_coupling boolean

Enables/Disables use of channel coupling, which is an optional AC-3

feature that increases quality by combining high frequency

information from multiple channels into a single channel. The per-

channel high frequency information is sent with less accuracy in

both the frequency and time domains. This allows more bits to be

used for lower frequencies while preserving enou gh information to

reconstruct the high frequencies. This option is enabled by default

for the floating-point encoder and should genera lly be left as

enabled except for testing purposes or to increa se encoding speed.

-1

auto

Selected by Encoder (default)

0

off Disable Channel Coupling

1

on Enable Channel Coupling

-cpl_start_band number

Coupling Start Band. Sets the channel coupling s tart band, from 1

to 15. If a value higher than the bandwidth is u sed, it will be

reduced to 1 less than the coupling end band. If auto is used, the

start band will be determined by the encoder bas ed on the bit rate,

sample rate, and channel layout. This option has no effect if

channel coupling is disabled.

-1

auto

Selected by Encoder (default)

VIDEO ENCODERS

A description of some of the currently avail able video encoders

follows.

libvpx

VP8 format supported through libvpx.

Requires the presence of the libvpx headers and library during

configuration. You need to explicitly confi gure the build with

"--enable-libvpx".

Options

Mapping from FFmpeg to libvpx options with c onversion notes in

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parentheses.

threads

g_threads

profile

g_profile

vb rc_target_bitrate

g kf_max_dist

keyint_min

kf_min_dist

qmin

rc_min_quantizer

qmax

rc_max_quantizer

bufsize, vb

rc_buf_sz "(bufsize * 1000 / vb)"

rc_buf_optimal_sz "(bufsize * 1000 / vb * 5 / 6) "

rc_init_occupancy, vb

rc_buf_initial_sz "(rc_init_occupancy * 1000 / v b)"

rc_buffer_aggressivity

rc_undershoot_pct

skip_threshold

rc_dropframe_thresh

qcomp

rc_2pass_vbr_bias_pct

maxrate, vb

rc_2pass_vbr_maxsection_pct "(maxrate * 100 / vb )"

minrate, vb

rc_2pass_vbr_minsection_pct "(minrate * 100 / vb )"

minrate, maxrate, vb

"VPX_CBR" "(minrate == maxrate == vb)"

crf "VPX_CQ", "VP8E_SET_CQ_LEVEL"

quality

best

"VPX_DL_BEST_QUALITY"

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good

"VPX_DL_GOOD_QUALITY"

realtime

"VPX_DL_REALTIME"

speed

"VP8E_SET_CPUUSED"

nr "VP8E_SET_NOISE_SENSITIVITY"

mb_threshold

"VP8E_SET_STATIC_THRESHOLD"

slices

"VP8E_SET_TOKEN_PARTITIONS"

Alternate reference frame related

vp8flags altref

"VP8E_SET_ENABLEAUTOALTREF"

arnr_max_frames

"VP8E_SET_ARNR_MAXFRAMES"

arnr_type

"VP8E_SET_ARNR_TYPE"

arnr_strength

"VP8E_SET_ARNR_STRENGTH"

rc_lookahead

g_lag_in_frames

vp8flags error_resilient

g_error_resilient

For more information about libvpx see:

libx264

H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 fo rmat supported through

libx264.

Requires the presence of the libx264 headers and library during

configuration. You need to explicitly config ure the build with

"--enable-libx264".

Options

preset preset_name

Set the encoding preset.

tune tune_name

Tune the encoding params.

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fastfirstpass bool

Use fast settings when encoding first pass, defa ult value is 1.

profile profile_name

Set profile restrictions.

level level

Specify level (as defined by Annex A). Deprecat ed in favor of

x264opts.

passlogfile filename

Specify filename for 2 pass stats. Deprecated i n favor of x264opts

(see stats libx264 option).

wpredp wpred_type

Specify Weighted prediction for P-frames. Depre cated in favor of

x264opts (see weightp libx264 option).

x264opts options

Allow to set any x264 option, see x264 --fullhel p for a list.

options is a list of key=value couples separated by ":".

For example to specify libx264 encoding opti ons with ffmpeg:

ffmpeg -i foo.mpg -vcodec libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv

For more information about libx264 and the s upported options see:

DEMUXERS

Demuxers are configured elements in FFmpeg w hich allow to read the

multimedia streams from a particular type of file.

When you configure your FFmpeg build, all th e supported demuxers are

enabled by default. You can list all availab le ones using the configure

option "--list-demuxers".

You can disable all the demuxers using the c onfigure option

"--disable-demuxers", and selectively enable a single demuxer with the

option "--enable-demuxer=DEMUXER", or disabl e it with the option

"--disable-demuxer=DEMUXER".

The option "-formats" of the ff* tools will display the list of enabled

demuxers.

The description of some of the currently ava ilable demuxers follows.

image2

Image file demuxer.

This demuxer reads from a list of image file s specified by a pattern.

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The pattern may contain the string "%d" or " %0Nd", which specifies the

position of the characters representing a se quential number in each

filename matched by the pattern. If the form "%d0Nd" is used, the

string representing the number in each filen ame is 0-padded and N is

the total number of 0-padded digits represen ting the number. The

literal character % can be specified in th e pattern with the string

"%%".

If the pattern contains "%d" or "%0Nd", the first filename of the file

list specified by the pattern must contain a number inclusively

contained between 0 and 4, all the following numbers must be

sequential. This limitation may be hopefully fixed.

The pattern may contain a suffix which is us ed to automatically

determine the format of the images contained in the files.

For example the pattern "img-%03d.bmp" will match a sequence of

filenames of the form img-001.bmp, img-002.b mp, ..., img-010.bmp, etc.;

the pattern "i%%m%%g-%d.jpg" will match a se quence of filenames of the

form i%m%g-1.jpg, i%m%g-2.jpg, ..., i%m%g-10 .jpg, etc.

The size, the pixel format, and the format o f each image must be the

same for all the files in the sequence.

The following example shows how to use ffmpe g for creating a video from

the images in the file sequence img-001.jpeg , img-002.jpeg, ...,

assuming an input frame rate of 10 frames pe r second:

ffmpeg -i 'img-%03d.jpeg' -r 10 out.mkv

Note that the pattern must not necessarily c ontain "%d" or "%0Nd", for

example to convert a single image file img.j peg you can employ the

command:

ffmpeg -i img.jpeg img.png

applehttp

Apple HTTP Live Streaming demuxer.

This demuxer presents all AVStreams from all variant streams. The id

field is set to the bitrate variant index nu mber. By setting the

discard flags on AVStreams (by pressing a or v in ffplay), the

caller can decide which variant streams to a ctually receive. The total

bitrate of the variant that the stream belon gs to is available in a

metadata key named "variant_bitrate".

sbg

SBaGen script demuxer.

This demuxer reads the script language used by SBaGen

to generate binaur al beats sessions. A SBG

script looks like that:

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-SE

a: 300-2.5/3 440+4.5/0

b: 300-2.5/0 440+4.5/3

off: -

NOW == a

+0:07:00 == b

+0:14:00 == a

+0:21:00 == b

+0:30:00 off

A SBG script can mix absolute and relative t imestamps. If the script

uses either only absolute timestamps (includ ing the script start time)

or only relative ones, then its layout is fi xed, and the conversion is

straightforward. On the other hand, if the s cript mixes both kind of

timestamps, then the NOW reference for relat ive timestamps will be

taken from the current time of day at the ti me the script is read, and

the script layout will be frozen according t o that reference. That

means that if the script is directly played, the actual times will

match the absolute timestamps up to the soun d controllers clock

accuracy, but if the user somehow pauses the playback or seeks, all

times will be shifted accordingly.

MUXERS

Muxers are configured elements in FFmpeg whi ch allow writing multimedia

streams to a particular type of file.

When you configure your FFmpeg build, all th e supported muxers are

enabled by default. You can list all availab le muxers using the

configure option "--list-muxers".

You can disable all the muxers with the conf igure option

"--disable-muxers" and selectively enable / disable single muxers with

the options "--enable-muxer=MUXER" / "--disa ble-muxer=MUXER".

The option "-formats" of the ff* tools will display the list of enabled

muxers.

A description of some of the currently avail able muxers follows.

crc

CRC (Cyclic Redundancy Check) testing format .

This muxer computes and prints the Adler-32 CRC of all the input audio

and video frames. By default audio frames ar e converted to signed

16-bit raw audio and video frames to raw vid eo before computing the

CRC.

The output of the muxer consists of a single line of the form:

CRC=0xCRC, where CRC is a hexadecimal number 0-padded to 8 digits

containing the CRC for all the decoded input frames.

For example to compute the CRC of the input, and store it in the file

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out.crc:

ffmpeg -i INPUT -f crc out.crc

You can print the CRC to stdout with the com mand:

ffmpeg -i INPUT -f crc -

You can select the output format of each fra me with ffmpeg by

specifying the audio and video codec and for mat. For example to compute

the CRC of the input audio converted to PCM unsigned 8-bit and the

input video converted to MPEG-2 video, use t he command:

ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f crc -

See also the framecrc muxer.

framecrc

Per-frame CRC (Cyclic Redundancy Check) test ing format.

This muxer computes and prints the Adler-32 CRC for each decoded audio

and video frame. By default audio frames are converted to signed 16-bit

raw audio and video frames to raw video befo re computing the CRC.

The output of the muxer consists of a line f or each audio and video

frame of the form: stream_index, frame_dts, frame_size, 0xCRC, where

CRC is a hexadecimal number 0-padded to 8 di gits containing the CRC of

the decoded frame.

For example to compute the CRC of each decod ed frame in the input, and

store it in the file out.crc:

ffmpeg -i INPUT -f framecrc out.crc

You can print the CRC of each decoded frame to stdout with the command:

ffmpeg -i INPUT -f framecrc -

You can select the output format of each fra me with ffmpeg by

specifying the audio and video codec and for mat. For example, to

compute the CRC of each decoded input audio frame converted to PCM

unsigned 8-bit and of each decoded input vid eo frame converted to

MPEG-2 video, use the command:

ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f framecrc -

See also the crc muxer.

image2

Image file muxer.

The image file muxer writes video frames to image files.

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The output filenames are specified by a patt ern, which can be used to

produce sequentially numbered series of file s. The pattern may contain

the string "%d" or "%0Nd", this string speci fies the position of the

characters representing a numbering in the f ilenames. If the form

"%0Nd" is used, the string representing the number in each filename is

0-padded to N digits. The literal character % can be specified in the

pattern with the string "%%".

If the pattern contains "%d" or "%0Nd", the first filename of the file

list specified will cont

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